Early on February 17, many people’s phones were swept by a news story titled “Favipiravir, the first drug with potential treatment for neoconjunctivitis, is approved for marketing in China”. Favipiravir is the first drug with potential efficacy in neocrown pneumonia to be approved for marketing during the epidemic.
At first glance, the news made people think that there was a first antiviral drug to treat Neocoronavirus pneumonia. But when you think about it, it doesn’t seem that way.
What is Favipiravir?
Favipiravir (a drug that can be used to treat pneumonia) is an antiviral.
Favipiravir (also known as favipiravir), like Remdesivir, is an RNA (ribonucleic acid) polymerase inhibitor, a broad-spectrum antiviral drug that inhibits viral proliferation primarily by blocking viral nucleic acid replication.
Faprevir was approved in Japan in March 2014 for the treatment of novel and relapsing forms of influenza. Preclinical pharmacodynamics showed that it was effective against not only seasonal influenza viruses, but also swine-derived as well as highly pathogenic avian influenza< /a> of various influenza viruses showed antiviral activity.
Is favipiravir the first drug approved for the treatment of Neocoronavirus?
In fact, this is a misinterpretation. Hazen Pharma announced on February 16 that the State Drug Administration approved the issuance of the Drug Registration Approval for Favipiravir tablets for the indication: for the treatment of novel or re-pandemic influenza in adults (only when other anti-influenza viral drugs are ineffective or ineffective). If it is for this indication of influenza, there are already a number of drugs that have been marketed and are in clinical use, such as oseltamivir and abirater.
Note here that the indication for the drug to be marketed is not for the treatment of Neocoronavirus, but for influenza virus.
The reason for the media and public misinterpretation may have been influenced by a separate approval document, the Drug Clinical Trial Approval. This document concludes with the following approval: In accordance with the Drug Administration Law, the Drug Registration Administration and the Special Drug Approval Procedure, Favipiravir was approved for clinical trials on a contingency basis after review by a special expert panel review. The indication is novel coronavirus pneumonia.
There is still a process from clinical trials to new therapeutic indications.
What is the efficacy of favipiravir for new coronaviruses?
Fapiviravir had in vitro inhibitory activity against the novel coronavirus 2019-nCoV in in vitro trials, but the half-inhibitory concentration (EC50) was much higher than that of raltegravir and chloroquine (data shown in the figure below). To clarify here, the half effective concentration, the smaller the value indicates better inhibition of the virus.
If we look at this trial, the potential efficacy of favipiravir is not as good as raltegravir and chloroquine.
On February 15, Zhang Xinmin, director of the Biological Center of the Ministry of Science and Technology, presented some of the current clinical status of fapreviravir at a State Council press conference:
“The clinical trial of famipiravir enrolled 70 patients (including the control group) and initially showed a more pronounced efficacy and lower adverse effects. The rate of viral nucleic acid regression was significantly higher in the dosing group than in the control group at days 3 to 4 after treatment.
Also, a clinical trial in Shenzhen showed that patients with neoclonal pneumonia treated with favipiravir initially showed significant efficacy and low adverse effects.
Shenzhen Third Hospital announced on February 14 that the clinical trial of favipiravir for the treatment of novel coronavirus pneumonia initiated by the National Clinical Medical Research Center for Infectious Diseases and Shenzhen Third Hospital (Second Affiliated Hospital of Southern University of Science and Technology) has achieved promising results. From the current enrollment, Favipiravir is safe and effective, and it is recommended to expand the scale of clinical application.”
But to see data on how effective favipiravir is and what the incidence of adverse reactions is, we will have to wait until the results of the interim analysis and full results of these clinical trials are published.